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os1

[os] /ɒs/
noun, plural ossa
[os-uh] /ˈɒs ə/ (Show IPA)
1.
Anatomy, Zoology. a bone.
Origin
1540-1550
1540-50; < Latin

os2

[os] /ɒs/
noun, plural ora
[awr-uh, ohr-uh] /ˈɔr ə, ˈoʊr ə/ (Show IPA)
1.
Anatomy, Zoology. a mouth or orifice of the body.
Origin
1730-40; < Latin ōs mouth

os3

[ohs] /oʊs/
noun, plural osar
[oh-sahr] /ˈoʊ sɑr/ (Show IPA)
1.
Geology. an esker, especially when of great length.
Origin
< Swedish ås (plural åsar) ridge

O, o

[oh] /oʊ/
noun, plural O's or Os; o's or os or oes.
1.
the fifteenth letter of the English alphabet, a vowel.
2.
any spoken sound represented by the letter O or o, as in box, note, short, or love .
3.
something having the shape of an O .
4.
a written or printed representation of the letter O or o.
5.
a device, as a printer's type, for reproducing the letter O or o.

O

[oh] /oʊ/
interjection
1.
(used before a name in direct address, especially in solemn or poetic language, to lend earnestness to an appeal):
Hear, O Israel!
2.
(used as an expression of surprise, pain, annoyance, longing, gladness, etc.)
noun, plural O's.
3.
the exclamation “O.”.
Origin
1125-75; Middle English < Old French < Latin ō
Can be confused
O, oh, owe.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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British Dictionary definitions for os'

o

/əʊ/
noun (pl) o's, O's, Os
1.
the 15th letter and fourth vowel of the modern English alphabet
2.
any of several speech sounds represented by this letter, in English as in code, pot, cow, move, or form
3.
another name for nought

O1

symbol
1.
(chem) oxygen
2.
a human blood type of the ABO group See universal donor
3.
(logic) a particular negative categorial proposition, such as some men are not married: often symbolized as SoP Compare A, E, I2
abbreviation
4.
(Austral, slang) offence
Word Origin
(for sense 3) from Latin (neg)o I deny

O2

/əʊ/
interjection
1.
a variant spelling of oh
2.
an exclamation introducing an invocation, entreaty, wish, etc: O God!, O for the wings of a dove!

os1

/ɒs/
noun (pl) ossa (ˈɒsə)
1.
(anatomy) the technical name for bone
Word Origin
C16: from Latin: bone; compare Greek osteon

os2

/ɒs/
noun (pl) ora (ˈɔːrə)
1.
(anatomy, zoology) a mouth or mouthlike part or opening
Word Origin
C18: from Latin

os3

/əʊs/
noun (pl) osar (ˈəʊsɑː)
1.
another name for esker
Word Origin
C19 osar (pl), from Swedish ås (sing) ridge

Os

Chemical symbol
1.
osmium

OS

abbreviation
1.
Old School
2.
Old Style (method of reckoning dates)
3.
Ordinary Seaman
4.
(in Britain) Ordnance Survey
5.
outsize
6.
Old Saxon (language)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for os'

o

interjection of fear, surprise, admiration, etc.; see oh.

O

blood type, 1926, originally "zero," denoting absence of A and B agglutinogens.

Online Etymology Dictionary, © 2010 Douglas Harper
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os' in Medicine

o
The Greek letter omicron. Entries beginning with this character are alphabetized under omicron.

O 1

The symbol for the element oxygen.

O 2
abbr.
oculus

os 1 (ŏs)
n. pl. o·ra (ôr'ə)

  1. An opening into a hollow organ or canal.

  2. The oral cavity; mouth.

os 2 (ŏs)
n. pl. os·sa (ŏs'ə)
Bone.

Os
The symbol for the element osmium.

OS abbr.
Latin oculus sinister (left eye)

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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os' in Science
O  
The symbol for oxygen.
Os  
The symbol for osmium.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Related Abbreviations for os'

o

  1. Latin octarius (pint)
  2. octavo
  3. ohm

O

  1. old
  2. Oriental (as in personal ads, but usually A, Asian)
  3. out
  4. outstanding

Os

osmium

OS

  1. offscreen
  2. Old Saxon
  3. Old Style (calendar)
  4. operating system
  5. ordinary seaman
  6. out of stock
The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Encyclopedia Article for os'

Os

(Os), chemical element, one of the platinum metals of Group VIIIb of the periodic table and the densest naturally occurring element. A gray-white metal, osmium is very hard, brittle, and difficult to work, even at high temperatures. Of the platinum metals it has the highest melting point, so fusing and casting are difficult. Osmium wires were used for filaments of early incandescent lamps before the introduction of tungsten. It has been used chiefly as a hardener in alloys of the platinum metals, though ruthenium has generally replaced it. A hard alloy of osmium and iridium has been used for tips of fountain pens and phonograph needles, and osmium tetroxide is used in certain organic syntheses.

Learn more about Os with a free trial on Britannica.com
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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2
2
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